In recent years, organic electroluminescent elements attract attention as new luminescent elements. In this element, the holes injected from an anode and the electrons injected from a cathode are recombined in an organic emitting layer held between both the electrodes, and C. W. Tang et al. of Kodak demonstrated for the first time that it emitted light at a high luminance at a low voltage (App. Phys. Lett. 51 (12) 21, p. 913, 1987).
FIG. 37 is a sectional view showing a typical structure of an organic electroluminescent element. A hole transport layer 5, an organic emitting layer 6 and second electrodes (cathodes) 8 are laminated on transparent first electrodes (anodes) 2 formed on a glass substrate 1, and the light emitted due to the drive by a drive source 9 is taken outside through the first electrodes and the glass substrate. Such organic electroluminescent elements, with a thin thickness and under low voltage driving, can emit light at a high luminance and also allow multicolored luminescence by selecting organic luminescent materials. Their application as electroluminescent devices such as display elements and displays is being actively studied.
In these case, for example, in a passive matrix type color display as shown in FIGS. 1 to 3, a technique for highly precisely patterning at least an organic emitting layer and second electrodes is needed, and in an active matrix type color display, a technique for highly precisely patterning at least an organic emitting layer is needed.
For such fine patterning, photolithography is conventionally used as a wet process. Japanese Patent Laid-Open (Kokai) No. Hei6-234969 discloses a technique for obtaining an element to allow application of photolithography by devising an organic material.
As methods for patterning the second electrodes without using any wet process, Japanese Patent Laid-Open (Kokai) Nos. Hei5-275172 and Hei8-315981 disclose partition techniques. In the technique of Japanese Patent Laid-Open (Kokai) No. Hei5-275172, partitions are arranged with intervals on a substrate, and an electrodes material is vapor-deposited on the substrate in an oblique direction. In the technique of Japanese Patent Laid-Open (Kokai) No. Hei8-315981, partitions with overhangs are formed on a substrate, and an electrode material is vapor-deposited on the substrate from within an angle range with the vertical direction as the center.
The conventional masking methods are general patterning methods without using any wet process. In these methods, a shadow mask is arranged before a substrate, and a deposit is vapor-deposited through apertures for patterning.
As a fine patterning method by masking, Japanese Patent Laid-Open (Kokai) No. Hei9-115672 discloses a masking technique using a shadow mask with a single layer structure. In this method, a shadow mask wider in mask portion than in aperture width is used for patterning an organic thin film layer and second electrodes for each luminescent color, to allow the production of a practical pitch passive matrix type color display.
On the other hand, though not relating to the method for producing an organic electroluminescent device, Japanese Patent Publication (Kokoku) No. Sho63-38421 discloses a technique for forming a wiring pattern by using a shadow mask with a laminate structure. In this method, a two-layer shadow mask consisting of meshes and a foil with a pattern formed, either of which is a magnetic material, is kept in contact with a substrate by a magnet, for vapor deposition. Since the meshes inhibit the deformation of apertures, a complicated wiring pattern such as a cyclic circuit portion and a curved thin circuit portion can be formed.